The MX037H/14 series like the other MXO37 series utilizes the internally heated resonator technology (IHR) providing very low power consumption, miniature sizes and fast warming up. Usage of the internal multiplication of frequency (by 3 or 5) enables extension of the operational frequencies up to 300 MHz and improvement as compared to the MXO37 series of the temperature stability and aging rate in 30-150 MHz range.